Scanning electron microscope images of pyrite

Scanning electron microscope images of pyrite

Scanning electron microscope images of pyrite (left) and partially oxidized pyrite (right)

Scanning electron microscope images of raspberry-shaped pyrite (left) and partially oxidized pyrite (right), as indicated by the red color, found at the Susquehanna Shale Hills Critical Zone Observatory. Fractures and erosion at the Earth’s surface control the rate of pyrite oxidation deep underground, leaving behind iron oxide “fossils” that retain pyrite’s shape.

IMAGE: Xin Gu